Experimental Analysis and Modeling of the Atmospheric Distillation Behavior of Biodiesels

Biodiesel stands out as a renewable biofuel with high potential to reduce dependence on fossil fuels and mitigate environmental impacts. Physical-chemical characterization is essential for assessing its quality and performance, with distillation being a fundamental tool for analyzing the volatility and thermal behavior of fuels, as recommended by international standards. In addition, its production is aligned with the Sustainable Development Goals (SDGs) by encouraging cleaner and more sustainable energy sources. In this study, biodiesels obtained from waste oil, cottonseed, canola, and sunflower were analyzed to investigate the atmospheric distillation behavior of these samples, comparing them with marine oil and the criteria established by ASTM standards. The distillation analyses were performed according to the ASTM D86 method in a Diana 300 automatic distiller, using 100 mL of each pure sample, under controlled heating, with temperature monitoring by thermocouple. The condensate was collected and the volume recovered, allowing the distillation curves to be obtained as a function of the distilled volume. Correlative modeling based on experimental data was employed, using an adapted methodology, correlating kinematic viscosity, density, and temperatures corresponding to 10%, 50%, and 90% of the distilled volume, parameters widely used and regulated by ASTM. Based on these data, the cetane index was estimated using a modification of the ASTM D4737 standard. The results were compared to the limits established by the ASTM D6751 standard, verifying that all biodiesels evaluated met the quality requirements and were compared to the base values of fossil diesel. However, it was observed that the distillation behavior of biodiesels differs from that of fossil diesel, especially in the higher boiling range, due to compositional differences between the fatty acid esters in biodiesel and the hydrocarbons in fossil diesel.